In recent years, mobile terminals (such as a smartphone and a tablet computer) are very popular. In addition, the mobile Internet has become increasingly widespread. When going out, a user usually uses these mobile terminals to listen to music, view a video, browse a website, or contact friends using instant messaging applications.
When using these applications, the user needs to watch a screen for a long time, and even wears headsets when listening to music, viewing a video, or playing a game. A phenomenon of walking on a street while using a mobile terminal has become increasingly common. When attention of a user is focused on a mobile terminal, the user usually fails to notice a change in an ambient environment or a sudden situation, thereby causing various accidents. For example, a user fails, when going across a road, to notice whether there is a coming car, a user fails, when taking an escalator, to notice that an end is approaching, and the like. Consequences of these accidents may be very slight, or may be very severe. However, existing mobile terminals fail to have a very effective method for avoiding the consequences of these accidents.